Rudy Fernandez added 17 points for Spain, silver medallists at the Beijing Games after losing in the final to the United States.
The Spaniards have several NBA players on their roster, including Gasol (Los Angeles Lakers), his brother Marc (Memphis Grizzlies) and Serge Ibaka (Oklahoma City Thunder).
"We got off to a slow start but we picked it up in the second and in the third we were able to break it open and open a big lead," Pau Gasol said. "Against better teams, we'll have to start better, but we are a team that likes to build, we play better as the tournament gets longer."
Some expect Spain to challenge the United States for the gold again — and that includes Australia coach Brett Brown, himself an American.
"They have a legitimate chance of knocking the United States," he said.
Marc Gasol added 12 points for Spain (2-0). Australia fell to 0-2.
Spain scored the first eight points of the third quarter and went on a 16-4 run keyed by Pau Gasol and Fernandez, who played with three stitches in the back of his head after crashing behind the basket late in the first half.
"I don't know what happened, I think I hit a camera," Fernandez said.
Spain scored the first eight points of the third quarter and went on a 16-4 run keyed by Pau Gasol and Fernandez.
Gasol had seven straight points as Spain built its lead to 49-34 and Fernandez sank three 3-pointers and had a dunk as Spain stretched the run to 24-5 to put the game away.
Spain played without Juan Carlos Navarro, one of its leading scorers. Navarro has been nursing a left-foot injury the entire year and it's unclear when he will return to the lineup.
"He felt a lot of pain at the end of the match against China. I don't know how many games he will miss," Spain coach Sergio Scariolo said.
The two-time European champions are already playing without guard Ricky Rubio of the Minnesota Timberwolves because of a knee injury.
Joe Ingles and Brad Newley led Australia with 12 points each.
Spain got 12 rebounds from Felipe Reyes and had 56 boards to Australia's 39.
"We did a good job, we got our best defence in the second and third quarters, we forced them into errors and got our big men inside," Scariolo said.